scholarly journals Investigations of the Absorption Front in High-Speed Laser Processing Up to 600 m/min

2021 ◽  
Vol 11 (9) ◽  
pp. 4015
Author(s):  
Peter Hellwig ◽  
Klaus Schricker ◽  
Jean Pierre Bergmann

High processing speeds enormously enlarge the number of possible fields of application for laser processes. For example, material removal for sheet cutting using multiple passes or precise mass corrections can be achieved by means of spatter formation. For a better understanding of spatter formation at processing speeds of several hundred meters per minute, characterizations of the processing zone are required. For this purpose, a 400 W single-mode fiber laser was used in this study to process stainless steel AISI 304 (1.4301/X5CrNi18-10) with speeds of up to 600 m/min. A setup was developed that enabled a lateral high-speed observation of the processing zone by means of a glass plate flanking. This approach allowed for the measurement of several dimensions, such as the penetration depth, spatter formation, and especially, the inclination angle of the absorption front. It was shown that the loss of mass started to significantly increase when the absorption front was inclined at about 60°. In combination with precise weighings, metallographic examinations, and further external process observations, these findings provided an illustration of four empirical process models for different processing speeds.

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
I. S. Amiri ◽  
P. G. Kuppusamy ◽  
Ahmed Nabih Zaki Rashed ◽  
P. Jayarajan ◽  
M. R. Thiyagupriyadharsan ◽  
...  

AbstractHigh-speed single-mode fiber-optic communication systems have been presented based on various hybrid multiplexing schemes. Refractive index step and silica-doped germanium percentage parameters are also preserved during their technological boundaries of attention. It is noticed that the connect design parameters suffer more nonlinearity with the number of connects. Two different propagation techniques have been used to investigate the transmitted data rates as a criterion to enhance system performance. The first technique is soliton propagation, where the control parameters lead to equilibrium between the pulse spreading due to dispersion and the pulse shrinking because of nonlinearity. The second technique is the MTDM technique where the parameters are adjusted to lead to minimum dispersion. Two cases are investigated: no dispersion cancellation and dispersion cancellation. The investigations are conducted over an enormous range of the set of control parameters. Thermal effects are considered through three basic quantities, namely the transmission data rates, the dispersion characteristics, and the spectral losses.


2015 ◽  
Vol 36 (2) ◽  
Author(s):  
Vikrant Sharma ◽  
Anurag Sharma ◽  
Dalvir Kaur

AbstractIn this paper, performance analysis of high-speed superdense wavelength-division-multiplexing (SDWDM) optical add–drop multiplexer (OADM) optical ring network for 6 nodes, 45 wavelengths having channel spacing of 0.2 nm on 300 km unidirectional nonlinear single-mode fiber ring of 10 Gbit/s has been reported. The performance optimization of the system by comparing different modulation formats has been reported on the basis of eye diagram and bit error rate (BER). It has been reported that CSRZ modulation format can achieve BER as better as e-24, which gives best performance. This paper also presents a study of performance degradation caused by the crosstalk and the effect of channel spacing on SWDM system.


Author(s):  
J. Hayashi ◽  
S. Fujita ◽  
Y. Isoda ◽  
T. Uji ◽  
M. Shikada ◽  
...  

2017 ◽  
Vol 3 (2) ◽  
pp. 227-230
Author(s):  
Jonas Golde ◽  
Lars Kirsten ◽  
Edmund Koch

AbstractWe present an approach for polarization sensitive optical coherence tomography (PS-OCT) that solely requires a modification of the light source, a buffered swept source laser. For this purpose a single-mode fiber-based Fourier domain mode locked laser is extended by fourfold buffering with manual fiber polarization controllers to emit alternating sweep polarizations, while the polarization contrast calibration is realized by a high-speed polarimeter. As the introduced setup utilizes standard scanning and detection units, the proposed method is a promising way to enhance various swept source OCT systems by polarization sensitive imaging. Preliminary measurements of a human finger nail with different polarization contrasts demonstrate the feasibility of the concept.


2021 ◽  
Vol 11 (9) ◽  
pp. 4284
Author(s):  
Oskars Ozolins ◽  
Xiaodan Pang ◽  
Aleksejs Udalcovs ◽  
Richard Schatz ◽  
Sandis Spolitis ◽  
...  

We experimentally evaluate the high-speed on–off keying (OOK) and four-level pulse amplitude modulation (PAM4) transmitter’s performance in C-band for short-reach optical interconnects. We demonstrate up to 100 Gbaud OOK and PAM4 transmission over a 400 m standard single-mode fiber with a monolithically integrated externally modulated laser (EML) having 100 GHz 3 dB bandwidth with 2 dB ripple. We evaluate its capabilities to enable 800 GbE client-side links based on eight, and even four, optical lanes for optical interconnect applications. We study the equalizer’s complexity when increasing the baud rate of PAM4 signals. Furthermore, we extend our work with numerical simulations showing the required received optical power (ROP) for a certain bit error rate (BER) for the different combinations of the effective number of bits (ENOB) and extinction ratio (ER) at the transmitter. We also show a possibility to achieve around 1 km dispersion uncompensated transmission with a simple decision feedback equalizer (DFE) for a 100 Gbaud OOK, PAM4, and eight-level PAM (PAM8) link having the received power penalty of around 1 dB.


Photonics ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 31
Author(s):  
Nikolaos-Panteleimon (Pandelis) Diamantopoulos ◽  
Suguru Yamaoka ◽  
Takuro Fujii ◽  
Hidetaka Nishi ◽  
Koji Takeda ◽  
...  

Near-future upgrades of intra data center networks and high-performance computing systems would require optical interconnects capable of operating at beyond 100 Gbps/lane. In order for this evolution to be achieved in a sustainable way, high-speed yet energy-efficient transceivers are in need. Towards this direction we have previously demonstrated directly-modulated lasers (DMLs) capable of operating at 50 Gbps/lane with sub-pJ/bit efficiencies based on our novel membrane-III-V-on-Si technology. However, there exists an inherent tradeoff between modulation speed and power consumption due to the carrier-photon dynamics in DMLs. In this work, we alleviate this tradeoff by introducing photon–photon resonance dynamics in our energy-efficient membrane DMLs-on-Si design and demonstrate a device with a maximum 3-dB bandwidth of 47.5 GHz. This denotes a bandwidth increase of more than 2x times compared to our previous membrane DMLs-on-Si. Moreover, the DML is capable of delivering 60-GBaud PAM-4 signals under Ethernet’s KP4-FEC threshold (net data rate of 113.42 Gbps) over 2-km of standard single-mode fiber transmission. DC energy-efficiencies of 0.17 pJ/bit at 25 °C and 0.34 pJ/bit at 50 °C have been achieved for the > 100-Gbps signals. Deploying such DMLs in an integrated multichannel transceiver should ensure a smooth evolution towards Terabit-class Ethernet links and on-board optics subsystems.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Navjot Singh ◽  
Bharat Naresh Bansal

Abstract Wavelength division multiplexed passive optical is promising technique to achieve a high data rate and large number of user. The notable advantages of WDM PON is the combination of reliability, cheap in cost, accessible bandwidth, high security, large optical reach and it can support large number of ONU. There are multiple approaches to achieve high-speed WDN PON using different transmission techniques. In WDM, multiple lasers are required which increase the cost of the system. To reduce cost, an optical multicarrier generation system is proposed. An economical multiple carrier generation with the incorporation of sine generator and Mach–Zehndar modulator is demonstrated. Utmost work of sine generator and dual drive modulator was to attain low cost functioning of passive optical networks. Multicarrier generation was done and replacement of laser carriers with optical multicarrier generator. Carriers were generated with the frequency spacing of 20 GHz and these carriers were used in the passive optical networks with the tone-to-noise ratio of 40 dB, amplitude difference of 1.4 dB. For the transmission of downstream in the PON, differential phase shift keying was employed at 10 Gbps data speed. Transmission distance achieved was 30 km using single-mode fiber and this was a part of optical distribution network. Optical network unit was next part after ODN and signals were received with balanced receiver. Moreover, half signal was given to intensity modulator for the signal re-modulation. Bit error rate of 10–9 was achieved at all channels in the downstream. An upstream of 10 Gbps was accomplished in the passive optical network.


2020 ◽  
Author(s):  
Taylor A. Hinsdale ◽  
Sjoerd Stallinga ◽  
Bernd Rieger

Structured Illumination Microscopy (SIM) is a widely used imaging technique that doubles the effective resolution of widefield microscopes. Most current implementations rely on diffractive elements, either gratings or programmable devices, to generate structured light patterns in the sample. These can be limited by spectral efficiency, speed, or both. Here we introduce the concept of fiber SIM which allows for camera frame rate limited pattern generation and manipulation over a broad wavelength range. Illumination patterns are generated by coupling laser beams into radially opposite pairs of fibers in a hexagonal single mode fiber array where the exit beams are relayed to the microscope objective’s back focal plane. The phase stepping and rotation of the illumination patterns are controlled by fast electro-optic devices. We achieved a rate of 111 SIM frames per second and imaged with excitation patterns generated by both 488 nm and 532 nm lasers.


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